Method of producing silicon carbid.



F. J. TONE. METHOD OF PRODUCING SILICON OARBID.

APPLIOATION FILED JULY 11. 1908.

Patented Dec.29, 1908.

INVENTOR 530. am

I I! u WITNESSES FRANK J. TONE, NIAGARA FALLS, NEW

COMPANY, OF NIAGARA FALLS, NEW YOR YORK, ASSIGNOR TO THE OARBORUNDUM K, A CORPORATION OF PENNSYLVANIA.

METHOD OF PRODUCING SILICON GARBID.

Specification 0! Letters Patent.

yatented Dec. 29, 1908.

Application filed July 11, 1908. Serial No. name.

To all whom it may concern:

Be it known that I, FRANK J. TONE, of Niagara Falls, Niagara county, New York, have inyented a new and useful Method of Producing Silicon Oarbid or Electric-Furnace Products, of which the following is a full, clear, and exact description, reference being had to the accom anying drawings, forming part of this speci cation, in which Figure 1 is a vertical longitudinal section showing a furnace arranged for carrying out my invention; Fig. 2 is a cross-section of the same; and Fig. 3 is a view similar to Fig. 2 showing another form of furnace.

My invention relates to the manufacture of products by electric heat, and more articularly to the manufacture of silicon car id.

The object of the invention is to increase the efficiency of the process, and the output of the furnace; and to reduce the cost.

In the ordinary manufacture of silicon carbid, a mixture of silica and carbon is subjerted to heat in an electric furnace of the resistance type, the heat bein generated by a passage of current throug a resistance conductor. At the beginning of the heat the temperature of the resistance conductor and the charge mixture is substantially that of the surrounding air and the whole mass must be raised to a high temperature before the reaction begins. In heating the charge up to this critical temperature, a large amount of electric heat is generated at high ex ense.

have discovered that I can increase the efficiency and output of the furnace as well as reduce the cost, by utilizing the heat of combustion in initially heating the furnace, and that I can thereby bring the mixture up to nearly the reacting temperature. My invention, therefore, consists in initially heat ing the charge by the products of combustion, and thereafter continuing the operation by electrically developed heat.

Figs. 1 and 2 show one type of furnace for carrying out my invention. In these figures I show a rectangular furnace chamber having side Walls 2, 2, and end walls 3,v 3., through which extend the terminal electrodes 4, 4. A core of resistance material 5 connects the electrodes, and is surrounded by the charge of sand and coke 6. The bottom of the furnace is shown at 7, having a channel 8 for receiving products of combustion. The top of the furnace is closed by a refractory cover 9 having an outlet 10 for the products of combustion. The charge is held Within a receptacle having a bottom 11 supported above the main bottom by ribs or flanges 12, and side walls 13 inclose the charge, these being spaced apart from the outer furnace walls. The heated gases of combustion may be led from any suitable furnace and enter the base at the port 14. They traverse the longitudinal channel within the bottom, and then spread out under the bottom of the charge and ascend around the sides, and thence flow from the top of the charge to the top central outlet port. In their passage through the furnace they heat the inner receptacle and its inclosed charge. When the maximum degree of temperature has been obtained by the action of the heated gases, the electric current is supplied, and by its passage through the resistance core the charge is further heated to a temperature of conversion, and the operation goes on in the ordinary manner. The combustion gases may be continued through the electric heatin or not, as desired.

11 Fi 3 I show another form of furnace in which t e gases of combustion are brought into intimate contact with the charge. In this case the charge of silicious and carbonaceous material is provided with an excess of carbon. The furnace is of the well known type for producing silicon carbid except that supply pipes 15 project into the charge through the side walls 16 and the bottom 17 of the furnace, these leading from a main pipe 18. The-heated gases of combustion are passed into the main, and thence into the silicon carbid furnace, and when the charge in the vicinity of the inlet ports from the pipes is heated to redness, or to an ignition temperature, air or oxygen-bearing gases are introduced through the pipes. The oxygen combines with the excess carbon of the charge to heat the contents of the furnace. After this initial heating by combustion of the excess carbon, the electric current is turned on in'the same manner as in the previous form and the operation thereupon continued, as in the ordinary method.

The advantages of my invention result from the use of the heat of combustion for output of the furnace and decrease the cost of manufacture, since the electric heat is concentrated upon the reaction period.

Many changes may be made in the form and arrangement of the apparatus, and in the method of initial heating, Withoutdeparting from my invention. The process may also be applied to the production of any material in electric resistance furnaces.

I claim 1. The process of roducing silicon carbid, which consists in embedding a resistance conductor in a charge of silicious and carbonaceous material, initially heating the charge by combustion and then assing current through the resistance condhctor sufficient to produce silicon carbid.

2. A process of producing silicon carbid which consists in embedding a resistance conductor in a porous charge of silicious and carbonaceous material, initially heating the charge by passing heated gases therethrough, and then assing current through the resistance con uctor sufficient to produce silicon carbid.

3. A process of producing silicon carbid which consists in embedding a resistance conductor in a porous char e of silicious and carbonaceous material, sai charge containing an amount of carbon in excess of that required for the formation of silicon carbid, initially heating the charge by combustion, said combustion being accomplished by the combustion of the excess carbon of the charge mixture and oxygen-bearing gases introduced into said charge, and then passing current through the resistance conductor sufficient to produce silicon carbid.

4. A process of producing silicon carbid which consists in embedding a resistance conductor in a charge of silicious and carbonaceous material, initially heating the charge by combustion and then in addition to combustion heating, passing current through the resistance conductor suflicient to roduce silicon carbid.

my hand.

' FRANK J. TONE.

Witnesses:

ASHMEAD G. RODGERS, FRED I. PIERCE.

11 testimony whereof, Ihave hereunto set 

